Data collected from the Atmospheric Radiation Measurement Climate Research Facility’s Southern Great Plains site (shown here) was used to evaluate and compare climate model simulations of precipitation.

Precipitation is difficult to represent in global climate models. Although most single-column models can reproduce the observed average precipitation reasonably well, there are significant differences in their details, including mean precipitation intensity. Scientists evaluated the performance of seven single-column models, used by global models to complex processes, by comparing simulated surface precipitation with observations.

The different single-column models’ performances and associations with large-scale conditions provide insights on how to improve climate models’ representation of convection, the movement of heat or air through fluids. Convection is integral to forming storm clouds. The insights gained here will also improve approaches for future testing.

Summary

Precipitation is one of the most poorly parameterized physical processes in global climate models. Scientists often use a single grid-box column of a global climate model or a single-column model to more efficiently study and test the process representations or parameterization schemes in global climate models. The single-column model approach is also a key strategy of the U.S. Department of Energy’s (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility and Atmospheric System Research activity.

However, most single-column model intercomparison studies organized by ARM have been focused on special cases or week- to month-long periods. To make a statistically meaningful comparison and evaluation of modeled precipitation, researchers conducted 3-year-long single-column model simulations of seven global climate models participating in the Fast-physics System Testbed and Research (FASTER) project at the ARM Southern Great Plains site.

Results of the study, conducted by DOE scientists at Brookhaven National Laboratory, show that although most single column models can reproduce the observed average precipitation reasonably well, there are significant differences in their details.

These variations (both among models and between models and observations) include differences between daytime and nighttime, warm and cold seasons, frequency and mean precipitation intensity, and convective and stratiform partition. Further analysis reveals distinct meteorological backgrounds for large underestimation and overestimation precipitation events. The former occur in strong ascending regimes with negative low-level horizontal heat and moisture influx, while the latter occur in the weak or moderate ascending regimes with positive low-level horizontal heat and moisture influx.

Funding

This work is part of the FASTER project supported by the U.S. Department of Energy’s Earth System Modeling program.

Die letzten 5 Focus-News des innovations-reports im Überblick:

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...